Pump assembly with user-accessible wet region

ABSTRACT

A centrifugal pump assembly, with an electric motor, arranged in a stator housing, wherein a box, containing an electrical board and closed at the free end by a lid, is arranged at an axial end of the stator housing. The pump assembly includes a wet region, further having a plug which has, at one end, a contour adapted to enter a hole connected to the wet region, acting as a flow control element, and, at the other end, a head adapted to be easily accessible to the user. The plug has such a length that the outer surface of the head is at a level that is proximate to the level of the lid of the box in a closed configuration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to, and claims the benefit of, Italian Patent Application No. 102017000103805, filed on Sep. 18, 2017, the contents of which are herein incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a centrifugal pump assembly with electric motor.

BACKGROUND

Conventional centrifugal pump assemblies are substantially composed of a hollow body provided with intake and delivery ducts and containing one or more impellers interleaved by diffusers and keyed on the shaft of an electric motor enclosed within a motor casing that isolates it from the pumping liquid.

An electrical board, contained in a box, powers and controls the operation of the motor.

These known methods have drawbacks and aspects that can be improved.

Normally, the release of the impeller shaft, after long periods of inactivity, is performed automatically by an electronically controlled system, but this may not always be sufficiently effective.

Furthermore, the plug, where present, has a size and shape that make it difficult to access for the user.

Moreover, the plug, where present, has such a volume that it can generate a thermal bridge from the wet region and the surrounding region, causing damage.

SUMMARY

The aim of the present disclosure is to provide a centrifugal pump assembly with electric motor that is capable of improving the background art in one or more of the aspects indicated above.

Within this aim, an object of the disclosure is to provide a centrifugal pump assembly with electric motor and electronics, which comprises a plug for manual release of the shaft by the user that has a more compact volume with respect to similar commercially available pumps.

Another object of the disclosure is to provide a centrifugal pump assembly with electric motor in which said plug has such a shape and size that it can be easily accessed by the user.

A further object of the disclosure is to provide a centrifugal pump assembly, with electric motor, in which said plug has such a shape and size as to not generate thermal bridges.

Furthermore, an object of the present disclosure is to overcome the drawbacks of the background art in a manner which is alternative to any existing solutions.

Another object of the disclosure is to provide a centrifugal pump assembly with electric motor that is highly reliable, relatively easy to provide and at competitive costs.

This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by a centrifugal pump assembly with electric motor, arranged in a stator housing, in which a box, which contains an electrical board and is closed at the free end by a lid, is arranged at an axial end of said stator housing, said pump assembly comprising a wet region, characterized in that it comprises a plug which has, at one end, a contour adapted to enter a hole connected to said wet region, acting as a flow control element, and, at the other end, a head adapted to be easily accessible to the user, said plug having such a length that the outer surface of said head is at a level that is proximate to the level of the lid of said box in the closed configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the disclosure will become better apparent from the description of a preferred but not exclusive embodiment of the centrifugal pump assembly with electric motor according to the disclosure, illustrated by way of non limiting example in the accompanying drawings, wherein:

FIG. 1 is a sectional view of the pump assembly according to the disclosure; and

FIG. 2 is a perspective view of a plug for the pump assembly according to the disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to the FIGS. 1 and 2, the centrifugal pump assembly, with electric motor according to the disclosure, is designated generally by the reference numeral 10.

The centrifugal pump assembly 10 comprises a wet region which has intake and delivery ducts, not shown in the figures, of a known type, and an impeller which is also not shown in the figures, of a known type, which is immersed in the wet region.

The impeller is keyed on a shaft 17 of an electric motor 19 which is composed of a stator 12 and a rotor 18. The electric motor is arranged in a stator housing 11, which is adapted to isolate it from the wet region.

The centrifugal pump assembly 10 comprises, at one end, an electrical box 13, which contains an electrical board 14 adapted to control and power the electric motor 19. The electrical box 13 has a cylindrical shape and is closed at the free end by a lid 15. Advantageously, the electrical board 13 may also have a different extension.

In particular, the electric motor 19 and the electrical box 14 are extended along the same axis X, which coincides with the rotation axis of the motor and of the impeller. The electric motor 19 and the electrical box 14 are connected and rendered integral by the presence of an intermediate element 16. The intermediate element 16 is a connecting and/or covering element and has a tubular shape.

The electrical box 13 and the stator housing 11 have mutually complementary contact surfaces. One or more first pins 28 extend from the electrical box 13 and are adapted to be inserted in corresponding through holes 29 provided on the contact surface of the stator housing 11. The pins 28 are adapted to connect the box 13 and the stator housing 11 and to facilitate the assembly of the pump 10.

Likewise, the box 13 is provided with one or more second pins 30, which are extended inside the box 13 and in the direction of the lid 15 and the tips of which are adapted for insertion in corresponding holes provided on the surface of the lid 15 that is directed toward the inside of the box 13. The pins 30 are adapted to connect the box 13 and the lid 15 and to facilitate the assembly of the pump 10.

The electrical box 13 is provided internally with a tubular body 34 with an axis of extension that coincides with the axis X. The tubular body 34 is extended from the surface of contact with the stator housing 11 to the lid 15 of the electrical box 13. At the section of the tubular body 34, both the electrical board 14 and the lid 15 are provided with a through hole 36 with an axis of extension that coincides with the axis X.

Advantageously, the axis of extension of the hole may not coincide with the axis X but may be parallel thereto.

The through hole 36 and the tubular body 34 are adapted for the insertion of a plug 35 with one end in contact with the wet region. The tubular body 34 and the hole 36 of the lid 15 have such dimensions and shapes as to ensure interference and isolation of the electrical board 14 from the wet region even if the plug 35 is opened.

In particular, the plug 35 has, at one end, a contour 43 that is adapted to enter a hole which is connected to the wet region, acting as a flow control element, and, at the other end, a head 40 which is adapted to be easily accessible to the user. The plug 35 has a cylindrical shape and such a length that the external surface of the head 40 is at a level that is proximate to the level of the lid 15 of the box 13 in the closed configuration. The contour 43 comprises a disk-like end element 47 which continues in the hole, connected to the wet region, with a threaded element 42 adapted to define the fastening of the plug 35 in the threaded hole in a complementary manner. The disk-like element 47 has dimensions which are equal to or in case comparable with those of the head 40.

The head 40 is disc-shaped and has a notch 44 adapted for the insertion of the tip of a screwdriver in order to allow the unscrewing and screwing operation.

In one constructive variation, the plug 35 comprises a plug covering element, not visible in the figures, in order to conceal its presence and generate a more pleasant visual impact.

The plug 35 has an intermediate section 41 which is also disk-like and with dimensions which are similar to those of the head 40 in order to facilitate the insertion of the plug in the hole 36 and in the tubular body 34.

A first tubular section 45 with a diameter that is smaller than the diameter of the head 40 is interposed between the head 40 and the intermediate section 41. A second tubular section 46 with a diameter that is smaller than the diameter of the first tubular section 45 is interposed between the intermediate section 41 and the end element 47.

The presence of these cylindrical sections having a reduced diameter allows to avoid thermal bridges and allows to obtain a plug which is lighter for equal costs.

The plug 35 is made of brass by turning and all of its parts, which are designated in FIG. 2 by the reference numerals 40 to 47, are obtained from a single body.

Advantageously, the plug 35 can be made of stainless steel.

The seal between the wet region and the plug 35 is insured by an O-ring 37 of a known type; the seal between the wet region, the electrical box 13 and the stator housing 11 is ensured by a gasket 38 of a known type.

Male connecting plates 24 extend from the electrical board 14 and are adapted to enter female terminals 25 connected to the electric motor 19. In this manner, the board 14 can power and control the electric motor 19.

The electrical board 14 has, at one end, a connector 26 which is adapted to be inserted in an electric power supply terminal that is external to the pump. At the insertion region of the terminal, the box 13 has a tab 27 which protrudes with respect to the intermediate element 16.

It should be noted that the presence of the plug according to the disclosure allows release of the impeller, through the shaft, on the part of the user in a manual manner.

Furthermore, it should be noted that the dimensions and the shape of the plug allow easier access to the plug by the user.

It should also be noted that the presence in the plug of the cylindrical sections interposed between the head, central and end disk-like elements, with a reduced diameter with respect to them, allows to avoid the triggering of thermal bridges and defines a plug which has a lower weight for equal costs.

In practice it has been found that the disclosure achieves the intended aim and objects, providing a centrifugal pump assembly with electric motor, arranged in a stator housing, in which a box, which contains an electrical board and is closed at the free end by a lid, is arranged as an axial end of the stator housing, the pump assembly comprising a wet region, characterized in that it comprises a plug, which has, at one end, a contour adapted to enter the hole connected to the wet region, acting as a flow control element, and, at the other end, a head adapted to be easily accessible to the user, the plug having such a length that the outer surface of the head is at a level that is proximate to the level of the lid of the box in the closed configuration.

The disclosure thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may furthermore be replaced with other technically equivalent elements.

In practice, the materials used, as long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art. 

1. A centrifugal pump assembly, with an electric motor, arranged in a stator housing, wherein a box, containing an electrical board and closed at a free end by a lid, is arranged at an axial end of said stator housing, said centrifugal pump assembly comprising a wet region, and further comprising a plug which has, at one end, a contour adapted to enter a hole connected to said wet region, acting as a flow control element, and, at another end, a head adapted to be easily accessible to the user, said plug having such a length that an outer surface of said head is at a level that is proximate to the level of the lid of said box in a closed configuration.
 2. The centrifugal pump assembly according to claim 1, wherein said plug has an intermediate section having dimensions similar to dimensions of said head.
 3. The centrifugal pump assembly according to claim 1, wherein said plug has a plug covering element adapted to hide the presence of said plug.
 4. The centrifugal pump assembly according to claim 1, wherein said contour comprises a disk-like end element which continues in the hole, connected to said wet region, with a threaded element.
 5. The centrifugal pump assembly according to claim 1, wherein said head is disk-shaped and has a notch adapted for insertion of a tip of a screwdriver.
 6. The centrifugal pump assembly according to claim 2, wherein a first tubular section having a diameter that is smaller than said head is interposed between said head and said intermediate section and wherein a second tubular section having a diameter that is smaller than said first tubular section is interposed between said intermediate section and said disk-like end element.
 7. The centrifugal pump assembly according to claim 1, wherein said electrical box is provided internally with a tubular body with an axis of extension that coincides with, or is parallel to, an axis of extension of said box.
 8. The centrifugal pump assembly according to claim 7, wherein said tubular body has an extension from a surface of contact with said stator housing to said lid of said box.
 9. The centrifugal pump assembly according to claim 8, wherein at a section of said tubular body both said electrical board and said lid have a through hole with an axis of extension that coincides with the one of said tubular body.
 10. The centrifugal pump assembly according to claim 9, wherein said through hole and said tubular body are adapted for the insertion of said plug.
 11. The centrifugal pump assembly according to claim 1, wherein said electrical box and said stator housing have mutually complementary contact surfaces.
 12. The centrifugal pump assembly according to claim 1, wherein said box has one or more first pins adapted to be inserted in corresponding through holes which are present on a contact surface of the stator housing.
 13. The centrifugal pump assembly according to claim 12, wherein said box has one or more second pins, which are extended inside the box and in a direction of the lid, the tips of which are adapted for insertion in corresponding holes which are present on a surface of the lid that is directed toward the inside of the box.
 14. The centrifugal pump assembly according to claim 1, wherein said electrical board is provided with male connecting plates adapted to be inserted in female terminals connected to said electric motor.
 15. The centrifugal pump assembly according to claim 1, wherein said electrical board has, at one end, a connector which is adapted to be inserted in an electric power supply terminal which is external to the pump. 